Portable water heater

ABSTRACT

A portable water heater comprising a housing supporting a pump and heat exchanger in fluid communication between an inlet and an outlet conduit. Burner means, positioned to supply heat to the heat exchanger, is connected to a control valve which is connectable to a supply of fuel. Igniter means, comprising electrodes positioned adjacent the burner means and manually operable electric potential generating means, is supported by the housing for initiating combustion of fuel by the burner means.

United-States Patent 1191 Watts June 12, 1973 [54] PORTABLE WATER HEATER FOREIGN PATENTS OR APPLICATIONS lnvenwrl James Watts, Bountiful, Utah 508,231 12/1954 Canada 126/350 R 4,137 /1897 GreatBritain 126/350 R [73] Asslgnee- System Beverly 671,009 4/1952 Great Britain 126/350 R Filedi g- 1971 Primary Examiner-William F. ODea [2 pp No; 1 7, 95 Assistant ExaminerWilliam C. Anderson Attorney-Alan C. Rose, Robert M. Angus and Alfred B. Levine [52] U.S. Cl 126/350 R [51] Int. Cl F24h H06 [58] Field 61 Search 126/350, 344; [571 ABSTRACT 122/1 A portable water heater comprising a housing supporting a pump and heat exchanger in fluid communication [56] References Cited between an inlet and an outlet conduit. Burner means,

UNITED STATES PATENTS positioned to supply heat to the heat exchanger, is con- 1 618 434 2/1927 Humphrey 126/350 R x nected to a control valve which is connectable to a sup- 3:509:388 4/1970 Mifune et 81.. 310/87 P y of fuel- Ignitef means, comprising electrodes P 1 19 171 3 1927 w m e1 22 40g x tioned adjacent the burner means and manually opera- 3,620,660 11/1971 Laurent 431/255 ble electric potential generating means, is supported by 2,366,080 12/l944 ga 41 /55 the housing for initiating combustion of fuel by the Branson et 81..... H burner means 3,533,380 10/1970 Finger 126/271.2 R

951,480 3/1910 Lively 122/115 5 Claims, 6 Drawing Figures 2,294,579 9/1942 Sherman 126/350 R 461 I9 17 2B 45 o '1 46 1 0g T \L' 29 '7 1 P 6; 27 20 47 49 E 22 o; s 44 r23 T \Y,48 46 1 I I I I 24 I 11 a. w. I

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JAMES E WATTS INVENTOR [WM/(Air? ATTORNEY PORTABLE WATER HEATER This invention relates to water heaters and particularly to portable water heaters suitable for use by campers.

There has been a long felt need for an efficient portable water heater for heating water in a minimal time and suitable for use by campers. Heretofore, campers requiring hot water have had to heat water in containers over a fire or cook stove. The time required to heat even a small amount of water was significantly long, for example, of the order of about to minutes.

It is an object of the present invention to provide a portable water heater suitable for use by campers which will efficiently and quickly heat water.

Another object of the present invention is to provide a portable water heater having means for attaching a portable source of fuel.

A portable water heater in accordance with the present invention includes a housing having a pump and a heat exchanger in fluid communication between inlet and outlet conduits. Burner means is provided adjacent the heat exchanger for supplying heat to water flowing therethrough. Control valve means, connectable to a supply of fuel, regulates fuel flow to the burner means. Igniter means, consisting of electrodes positioned adjacent the burner means ignites combustible vapor adjacent the burner means. Means is provided for supplying an electric potential to the electrodes.

One feature of the present invention resides in the provision of mounting means for mounting a standard propane tank such as the type ordinarily used by campers for supplying fuel to the burner means.

Another feature of the present invention resides in the provision of a piezoelectric crystal capable of being struck to generate an electric potential for the electrodes.

Another feature of the present invention resides in the fact that the water heater is compact, portable and lightweight so that it may easily be used by campers.

The above and other features of this invention will be more fully understood from the following detailed description and the accompanying drawings, in which:

FIG. 1 is a side view elevation, partly in cutaway cross-section, of a portable water heater in accordance with the presently preferred embodiment of the present invention;

FIG. 2 is a top view elevation of a heat exchanger for use in the water heater illustrated in FIG. 1;

FIG. 3 is a section view of the heat exchanger taken along line 33 in FIG. 2;

FIG. 4 is a top view elevation of means for generating an electric potential for use in the water heater illustrated in FIG. 1;

FIG. 5 is a section view of the means illustrated in FIG. 4 taken along line 5-5 in FIG. 4; and

FIG. 6 is a section view of a hand pump for use in the water heater illustrated in FIG. 1.

Referring to the drawings, there is illustrated a water heater 10 in accordance with the presently preferred embodiment of the present invention. Water heater 10 includes a substantially cylindrical housing 11 having its upper end closed by plate 12. Preferably, a handle 13 is pivotly mounted to plate I2 for carrying the water heater. Grommet 14 is fastened over the bottom edge of housing 11 so that the device may be set on a platform without marring the housing or the platform.

Pump 15, which includes handle 16, is mounted to plate 12. Fitting 17 is fastened to the wall of housing 11 and is adapted to receive a flexible conduit 18 for connection to a reservoir of water. By way of example, conduit 18 may be in fluid communication with a container of water (not shown) or even a flowing stream of water, such as a river. Fitting 17 is in fluid communication via conduit 19 to the inlet 20 of pump 15. The outlet 21 of pump I5 is connected via flexible conduit 22 to the inlet 23 of heat exchanger 24. Heat exchanger 24 is fastened within cylindrical housing 25 which in turn is fastened to exhaust conduit 26 supported by housing 11. Baffle 27 is disposed at an angle to direct hot gases from heat exchanger 24 to exhaust conduit 26. Preferably, a suitable heat insulation layer 28 is mounted to baffle 27. By way of example, layer 28 may be constructed of suitable asbestos or the like. Screen 29 is positioned at the outlet of exhaust 26.

Burner 30, which preferably includes a plurality of burner orifices (not shown) on burner surface 31, is mounted to conduit 32 which in turn is mounted to fitting 33. Fitting 33 is mounted to bracket 34 fastened to housing 11. As illustrated in FIG. 1, the open end of housing 25 is positioned above apertures 35 in housing 11. Hence, air is permitted to enter through apertures 35 to the interior of housing 25 to mix with fuel emitted from burner 30. Also, a suitable burner aperture 36 is provided in conduit 32 for mixing fuel and air to form a combustible mixture.

Bracket 37 is mounted to conduit 32 and supports a first electrode 38. Insulator 39 is sandwiched between electrode 38 and electrode 40, which is positioned immediately above burner surface 31. Electrode 40 is connected to spark generating means 41 by lead 42. Spark generating means 41, which is illustrated in greater detail in FIGS. 4 and 5 is mounted to bracket 34 by means of flange 43.

Outlet conduit 44 extends from heat exchanger 24 through opening 45 in housing 11. Preferably, a suitable rubber grommet 46 is provided at opening 45 and surrounding conduit 44.

Fuel conduit 46 is connected between control valve 47 and fitting 33 within housing 11. Conduit 46 extends outside of housing 1 l to control valve 47. Control valve 47, includes fastener means (not shown) adapted to be connected to a suitable supply tank 48 containing fuel. By way of example, one suitable control valve 47 is more fully disclosed in U. S. Pat. No. 2,793,504. Control valve 47 includes a serrated knob 49 for regulating the flow of fuel flowing from tank 48 to the burner 30. Mounting bracket 50 is fastened to housing 11 for supporting tank 48. Tank 48 may, for example, contain suitable pressurized propane, one such tank being commercially available from Bernz O Matic Corporation of Rochester, NY. Control valve 47 and mounting bracket 50 are positioned so that tank 48 rests on substantially the same surface as grommet 14.

Referring particularly to FIGS. 2 and 3, the details of heat exchanger 24 may be described. Heat exchanger 24 includes a substantially cylindrical housing 51 supporting a bundle of tubes 52. Preferably, and as illustrated in FIG. 2, the arrangement of tubes 52 is such as to provide an array of larger and smaller tubes which is repeated over each arc of housing 51. Header plate 53 encloses the outer surfaces of tubes 52 and of conduits 23 and 44 within housing 51, and header plate 54 encloses the outer surfaces of tubes 52 within hous- 3 ing 51. The ends of conduit 23 and 44 are closed by header plate 54, and slots 55 and 56 are provided in conduits 23 and 44 to permit fluid communication between the conduits and the region enclosed by header plates 53 and 54 within housing 51. Tubes 52 are opened at both ends so that heat from burner 30 passes through. the tubes to exhaust 26. (FIG. 1).

Referring particularly to FIGS. 4 and 5, spark generating means 41 may be described. Spark generating means 41 includes a substantially cylindrical housing 57 having a flat surface 58. Piezoelectric crystal 59 is positioned within bore 60 of housing 57 and is electrically connected to flange 43 of bracket 34 by means of threaded fastner 611. The opposite end of housing 57 is mounted to flange 62 on bracket 34. Connector 63 is provided for electrical connection to piezoelectric crystal 59. Lead 42 (FIG. 1) is connected to piezoelectric crystal 59 through connector 63.

Plunger 64 includes a pin 65 which extends through slot 66 in flat surface 58. The shank of plunger 64 extends into bore 67 of plunger 68 which in turn is connected to a push-button (not shown). Plunger 68 and the push-button extend through a suitable aperture (not shown) in housing 1 1 so that the same may be operated by an operator from outside of the housing. Plunger 64 also carries a hammer 69 adapted to strike piezoelectric crystal 59.

Slot 66 includes a shoulder 70 adapted to restrain pin 65 when in the position illustrated in FIG. 4. Bias spring I 71 biases plunger 64 toward crystal 59 and also biases plunger 64 radially in the direction of arrow 73 so that pin 65 is retained by shoulder 70. Compression spring 74 is provided between piezoelectric crystal 59 and plunger 64 to bias the plunger to the position illustrated in FIGS. 4 and 5. Plunger 68 also carries cam surface 72 which biases pin 65 in the direction opposite to arrow 73 when the plunger is axially moved.

In operation of the spark generating means illustrated in FIGS. 4 and 5, depression of the push-button on the shank of plunger 68 casues surface 72 to strike pin 65 thereby biasing pin 65 on plunger 64 in a direction opposite to arrow 73. When the pin clears shoulder '70, bias spring 71 biases plunger 64 so that hammer 69 strikes piezoelectric crystal 59 with a relatively hard or sharp force. The disturbance of piezoelectric crystal 59 causes a relatively high potential to be applied between flange 43 and connector 63. Electrode 38 (FIG. 1) is electrically connected to flange 43 through conduit 32 while electrode 40 is electrically connected to connector 63 by means of lead 42. Hence, a relatively high electric potential is imposed between electrodes 40 and 38 thereby causing a spark to appear across the gap between the electrodes. When the operator releases plunger 68, bias spring 74 biases plunger 64 and 68 axially to the right (as illustrated in FIGS. 4 and until pin 65 reaches shoulder 70. Bias spring 71 biases pulunger 64 to rotate about the axis of the plunger in the direction of arrow 73 so that pin 65 is restrained from axial movement.

FIG. 6 illustrates a pump for use in the water heater in accordance with the present invention. Pump 15 includes a housing 80 adapted to be mounted to the upper surface of plate 12 in FIG. 1. Housing 80 is threadably assembled to cap 81 to define a cavity 82 within housing 80 and cap 81. Preferably, seal means 83, such as a gasket, is disposed between cap 81 and hosuing 80 to provide a fluid seal between the elements. The lower end of housing includes port opening 84 in fluid communication with cavity 85 of fitting 20. A suitable serrated portion 87 is provided for connecion to a flexible conduit, such as conduit 19 in FIG. 1.

Piston 88 is pivotly mounted to arm 89 by pin 90. Piston 88 includes a plurality of port openings 91 providing fluid communication between the region above piston 88 and region 92 in the piston. Seal 93 is loosely coupled in region 92 and is adapted to seal against port 94 to control communication between region 92 and the region below piston 88. Arm 89 is pivotly mounted to cam 95 by pin 96. Cam 95 is connected to handle 16 by pin 98.Pin 98 is tightly fitted to cam 95 and handle 16 so that rotation of handle 16 about the axis of pin 98 rotates cam 95 in a like manner. Fitting 21 provides fluid communication to the region within cavity 82 above piston 88 and preferably includes a serrated portion 99 for connection to a suitable flexible conduit, such as conduit 22 in FIG. 1. Ball 100 is located in cavity 82 below piston 88 and is adapted to close port 84.

In operation of the pump illustrated in FIG. 6, handle 16 is manually reciprocated about the axis of pin 98 in the direction of arrow 101 causing reciprocal rotation of cam 95. Cam 95, which is universally joined to piston 88 by arm 89, casues piston 88 to reciprocate along axis 102 of the pump. As the piston is moved upwardly, as shown in FIG. 6, seal 93 closes against port 94 and water is drawn through fitting 20 and port opening 84 to displace ball 100 and enter cavity 82 below piston 88. When piston 88 is moved downwardly, ball 100 closes over port 84 to prevent the water in cavity 82 below the piston from flowing back out through fitting 20. seal 93 is forced upwardly by the increased pressure below the seal, thereby permitting water to flow through ports 94 and 91 into the region above piston 88. During the next upward stroke of piston 88, seal 93 again seals against port 94 to prevent water from flowing back to the region below the piston. Continued reciprocation of handle 16 draws mere water into the region above piston 88. The water is discharged through fitting 21. Hence, ball 100 and seal 93 operate as valve for the pump to prevent a back flow of water.

One feature of the present invention resides in the fact that housing 51 of heal exchanger-24 is snuggly received in housing 25 and above burner 30 and below exhaust conduit 26. Thus, substantially all heated gas fromburner 30 is directed through tubes 52 of the heat exchanger for maximum efficiency of the device. Preferably, the burner is located within housing 25 as shown in FIG. 1 so that a draft is created through housing 25 to increase the efficiency of the device. Suitable apertures (not shown) may be provided in the walls of housings 11 and 25 to enable the operator to view the burner.

Although one embodiment of the present invention has been described, it is to be understood that variation in design may be made within the spirit of the present invention. For example, the various elements may be positioned as shown in the copending application of James E. Watts, Ser. No. [68,522, filed Aug. 2, l97l, for Portable Water Heater, assigned to the same assignee as the present invention.

The present invention thus provides a portable water heater which is effective for heating water. The apparatus is particularly suitable for use by campers and the like. With the present invention, it is possible to heat water in about fifteen seconds, a substantially shorter period of time than previously required for heating water for campers. The water heater may be easily manufactured and is highly effective in use.

This invention is not to be limited by the embodiment shown in the drawings and described in the description, which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

What is claimed is:

l. A portable water. heater comprising: a first housing, said first housing including at least one aperture for permitting air to enter; a substantially cylindrical second housing supported within said first housing; a heat exchanger having a substantially cylindrical jacket mounted in an upper portion of said second housing, said second housing substantially enclosing said heat exchanger; a burner for burning fuel mounted in a lower portion of said second housing, said second housing having a substantially open lower end, air being permitted to enter through said aperture to the interior of said second housing to mix with fuel emitted from said burner, substantially all of the hot gases thus formed passing through said heat exchanger; an exhaust conduit connected to said second housing in communication with said heat exchanger at a region opposite from said burner; a conduit connected to said burner for providing fluid communication between said burner and a source of pressurized fuel; first and second electrodes positioned in said second housing adjacent said burner means; a piezo-electric crystal mounted on said first housing outside said second housing and electrically connected to said electrodes; manually operable striker means for striking said crystal to generate an electric spark between said electrodes; an inlet conduit supported by said first housing and adapted to be connected to a source of water; an outlet conduit supported by said first housing for discharging heated water; a manually operable pump supported by said first housing; means connecting said pump and said heat exchanger between said inlet and outlet conduits, whereby water flowing through said heat exchanger is heated by heat from said burner and fuel discharged from said burner is initially ignited by operating said striker means.

2. The device as claimed in claim 1 and further including a baffle disposed above said heat exchanger at angle with respect to the longitudinal axis of said second housing to direct hot gases from heat exchanger to said exhaust conduit.

3. Apparatus according to claim 1 wherein said pump includes a valve for preventing flow of water from said outlet conduit to said inlet conduit.

4. Apparatus according to claim 1 wherein said heat exchanger includes a plurality of substantially cylindrical tubes supported within said jacket, said tubes being arranged in a pattern which is repeated in each arc about the axis of said jacket, header plate means mounted to said jacket at each end thereof and in fluid sealing relation with each of said tubes to form a fluidsealed region in said jacket surrounding said tubes, one end of a first of said tubes being connected to said inlet conduit for said heat exchanger, one end of a second of said tubes being connected to said outlet for said heat exchanger, the interiors of said first and second tubes being in liquid communication with said fluidsealed region for discharging heated water under pressure, the remaining ones of said tubes being open at both ends so that heat from said burner passes through to said exhaust conduit, whereby heated gas from said burner means passes through the remaining ones of said tubes and water flows through said fluid-sealed region.

5. Apparatus according to claim 1 and further including a source of pressurized fuel and a control valve, said control valve supported by said first housing and having a connector adapted to be connected to said source of pressurized fuel, said source of fuel comprising a substantially cylindrical container containing pressurized combustible fuel, said apparatus further including a clamp supported on the outer cylindrical surface of said first housing for clamping said container to the cylindrical surface of said first housing. 

1. A portable water heater comprising: a first housing, said first housing including at least one aperture for permitting air to enter; a substantially cylindrical second housing supported within said first housing; a heat exchanger having a substantialLy cylindrical jacket mounted in an upper portion of said second housing, said second housing substantially enclosing said heat exchanger; a burner for burning fuel mounted in a lower portion of said second housing, said second housing having a substantially open lower end, air being permitted to enter through said aperture to the interior of said second housing to mix with fuel emitted from said burner, substantially all of the hot gases thus formed passing through said heat exchanger; an exhaust conduit connected to said second housing in communication with said heat exchanger at a region opposite from said burner; a conduit connected to said burner for providing fluid communication between said burner and a source of pressurized fuel; first and second electrodes positioned in said second housing adjacent said burner means; a piezo-electric crystal mounted on said first housing outside said second housing and electrically connected to said electrodes; manually operable striker means for striking said crystal to generate an electric spark between said electrodes; an inlet conduit supported by said first housing and adapted to be connected to a source of water; an outlet conduit supported by said first housing for discharging heated water; a manually operable pump supported by said first housing; means connecting said pump and said heat exchanger between said inlet and outlet conduits, whereby water flowing through said heat exchanger is heated by heat from said burner and fuel discharged from said burner is initially ignited by operating said striker means.
 2. The device as claimed in claim 1 and further including a baffle disposed above said heat exchanger at angle with respect to the longitudinal axis of said second housing to direct hot gases from heat exchanger to said exhaust conduit.
 3. Apparatus according to claim 1 wherein said pump includes a valve for preventing flow of water from said outlet conduit to said inlet conduit.
 4. Apparatus according to claim 1 wherein said heat exchanger includes a plurality of substantially cylindrical tubes supported within said jacket, said tubes being arranged in a pattern which is repeated in each 120* arc about the axis of said jacket, header plate means mounted to said jacket at each end thereof and in fluid sealing relation with each of said tubes to form a fluid-sealed region in said jacket surrounding said tubes, one end of a first of said tubes being connected to said inlet conduit for said heat exchanger, one end of a second of said tubes being connected to said outlet for said heat exchanger, the interiors of said first and second tubes being in liquid communication with said fluid-sealed region for discharging heated water under pressure, the remaining ones of said tubes being open at both ends so that heat from said burner passes through to said exhaust conduit, whereby heated gas from said burner means passes through the remaining ones of said tubes and water flows through said fluid-sealed region.
 5. Apparatus according to claim 1 and further including a source of pressurized fuel and a control valve, said control valve supported by said first housing and having a connector adapted to be connected to said source of pressurized fuel, said source of fuel comprising a substantially cylindrical container containing pressurized combustible fuel, said apparatus further including a clamp supported on the outer cylindrical surface of said first housing for clamping said container to the cylindrical surface of said first housing. 